In the process of sewing, when the thread carrying needle of a sewing machine penetrates the work piece, a loop taker grasps and expands a loop of thread drawn from the needle. In most sewing machines, this loop of thread is released by the loop taker, allowing the loop complete freedom of motion as the thread take-up, in tightening the stitch, draws the take-up limb of the thread loop up through the work piece. Occasionally, as the take-up limb of the thread loop is being drawn up through the work piece, due to friction between the take-up limb and the work limb, the work limb is also drawn up above the surface of the work piece where it may be trapped, forming a loose thread loop commonly called a halo.
U.S. Pat. No. 4,095,539 of R. E. Johnson, discloses a needle thread work limb retaining finger for separating the work limb from the take-up limb in a loop of thread to aid in the prevention of haloing. The use of this finger, however, significantly increases the thread demand since, during expansion and manipulation of the thread loop by the loop taker, the work limb must be draped over the finger which lies outside the normal path of the thread. This increased thread demand necessitates redesign of the thread take-up. In addition, after loop cast-off by the loop taker, the finger provides no position restraint on the work limb, and, considering the distance between the finger and the needle hole, through which both the work limb and the take-up limb must pass, the work limb and the take-up limb may still interengage possibly resulting in the work limb being frictionally drawn up with the take-up limb and being caught, forming a halo.